Engine Dies at Half A tank
 

Sputtering and stalling(Fuel Injection)

There's been some issues with engines in the fuel injected models sputtering and dying at half a tank of gas for no appearent reason. One cause for this is a fuel line inside the tank that is rubbing on the inside of the tank and wearing a hole in the line. When the tank gets to about 1/2 full, the motor will sputter and stall. You can try adding gas to the tank and it will run properly again indicating this problem. You can also diagnose it with a fuel pressure test, also the fuel pump will have a different sound to it.
Below is a pic of the line and what it looks like when it gets worn through.

http://www.hdforums.com/upfiles/2318...41172CD60E.jpg